Topic: Onions from seed dilemma

[RobinOfTheHood]

I have 2 trays of Ailsa Craig which have just germinated, and here are the instructions according to Tee Gee's website:

Germinate at a minimum temperature of 16°C (60°F)

As soon as they have germinated, normally in about five to six days, take covers off, and allow plenty light to the seedlings.

Grow on in Greenhouse at this temperature, ventilate as much as possible (depending upon the weather) giving maximum light at all times.

My dilemma is that they are at present on a warm windowsill in the house, with probably insufficient light, but the only other places that I have available are the shed (probably frost-free but maybe also a bit low on light) or the unheated greenhouse.

Which should it be?  ???

PS I think I know the answer, just need somebody to agree.... :)

[davyw1]

My first option would be to put them in the greenhouse during the day and bring them in the house as the light fades. Providing the GH temperature is above 40/45 deg they should be fine
The second option is to get some type of cheep heating which you can put in the GH during the day night and bring them in again at night.

[Barnowl]

I was surprised at the 16C. It seems high for onions since they are capable of germinating at below 10C.  My instinct would have been to harden them off over a few days and then leave them in the greenhouse - probably why my onions tend to be on the small side :)

Last year was mild but this year it looks like another cold snap is on the way so I may well be facing this problem myself in a couple of weeks. Hope TeeGee or someone comes along to clarify whether the temperature is necessary or simply best practice ..... :)

[Joolieeee]

I have a packet which I haven't done anything with yet - do you think I'm too late to sow them this year?

I was going to keep them in the conservatory as the greenhouse is unheated

Joolieeee

[Barnowl]

Pretty sure you can sow indoors/under cloches from January to February and then outdoors in March, depending on your region, but it's generally accepted that the earlier the better.

[Tee Gee]

Hi all,

Looks like I have a bit of explaining to do  ;)

Lets take germination first;

Germinate at a minimum temperature of 16°C (60°F)

This is an ideal temperature but as pointed out; they can be sown directly outdoors and they will germinate.

This is quite true but they won't germinate in 5-6 days, plus you won't be able to sow in this manner for another couple of months yet.

Similarly again something that has been pointed out;  they do better with a long growing season!

So if you have access to the right conditions by all means use them, if not let common sense prevail.

Grow on in Greenhouse at this temperature, ventilate as much as possible (depending upon the weather) giving maximum light at all times.

This is not imperative either but what I find is; if I don't do it, they take longer to develop after pricking out and I tend to lose a few plants.

I give them a couple of weeks on the hotbed to get the root system active again after the disturbance of 'pricking out'

I see someone else has been affected by a loss of plants perhaps this is your problem ............they may have cold feet!


Once I am satisfied usually a couple of weeks, I move them out of the heated greenhouse and into a cool one that I keep at around 4°-8°C (40°-45°F).

What is essential is; that they get 'maximum light' at all times.

My dilemma is that they are at present on a warm windowsill in the house, with probably insufficient light, but the only other places that I have available are the shed (probably frost-free but maybe also a bit low on light) or the unheated greenhouse.

As I have said above the temperature can be dropped substantially but light I always think is crucial, so as someone else has rightly said move them into a cool greenhouse during the day and watch the forecast for low temperatures.

If cold weather is forecast fetch them indoors overnight.

You could rig yourself up a fleece tunnel/cloche in the greenhouse and put this over them (removing it in the morning and putting it back on in the evening) this way they will have reasonable protection.

If you resort to the shed could you rig up a lead lamp plugged into a timer socket?

This way you could set the light for say 12 hours on and 12 hours off. This is not an ideal lighting method but it is better than none!

I hope that answers your question but as I have mentioned in the 'preface' of my website .............let common sense prevail when using this website!

Finally!

You say;

PS I think I know the answer, just need somebody to agree..

What is your answer?

[RobinOfTheHood]

My answer is, they are going in the cold greenhouse. I too thought that light would be more critical than temperature, especially as I have some of last years onions regrowing where they were left in the ground, despite weeks of sub-zero nights.

I will leave the tray lids on for a little extra frost protection, and they can take their chance in the cold.  :)

[Susiebelle]

Not my thread but just wanted to say thanks  Tee Gee for such a detailed answer, I found that very helpful.

[Barnowl]

Not my thread but just wanted to say thanks  Tee Gee for such a detailed answer, I found that very helpful.

Thanks from me as well  :)

[simmo116]

and me. but if i may be so rude as to hijack the thread. i have my onions in my coservatory. which is around a constant 10(cant find the little o for degrees so ill just type degrees.) but im not sure on watering times. at the moment im just giving them a good spray with an atomiser every other day. is this enough? oh and i have them on jiffy pellets.